Abstract
Objective
The aims of the present study were 1) to evaluate a method for identification of “slowly” distensible compartments of the respiratory system (rs), which are characterized by long mechanical time constants (RC) and 2) to identify “slowly” distensible rs-compartments in mechanically ventilated patients.
Design
Prospective studyon a physical lung model.
Setting
Intensive Care Unit, University Hospital, Tübingen.
Patients and participants
19 patients with severe lung injury (acute respiratory distress syndrome, ARDS) and on 10 patients with mild lung injury.
Measurements and results
Positive end-expiratory pressure (PEEP)-increasing and-decreasing steps of about 5 cmH2O were applied and the breath-by-breath differences of inspiratory and expiratory volumes (ΔV) were measured. The sequence of ΔVs were analyzed in terms of volume change in the “fast” compartment (Vfast), the “slow” compartment (Vslow), total change in lung volume (ΔVL) and mechanical time constant of the slow compartment (RCslow). Thirty-eight measurements in a lung model revealed a good correlation between the preset Vslow/ΔVL and Vslow/ΔVL measured: r2=0.91 The Vslow/ΔVL measured amounted to 0.94±0.15 of Vslow/ΔVL in the lung model. RCslow measured was 0.92±0.43 of the RCslow reference. Starting from a PEEP level of 11 cmH2O PEEP-increasing and PEEP-decreasing steps were applied to the mechanically ventilated patients. Three out of ten patients with mild lung injury (30%) and 7/19 patients with ARDS (36.8%) revealed “slowly” distensible rscompartments in a PEEP-increasing step, whereas 15/19 ARDS patients and 1/10 patients with mild lung injury showed “slowly” distensible rs-compartments in a PEEP-decreasing step (78.9% vs 10%,P<0.002, chi-square test).
Conclusions
The gas distribution properties of the respiratory system can be easily studied by a PEEP-step maneuver. The relative contribution of the “slow” units to the total increase of lung volume following a PEEP step could be adequately assessed. “Slowly” distensible rs-compartments could be detected in patients with severe and mild lung injury, however significantly more ARDS patients revealed “slow” rs-compartments in PEEP-decreasing steps. The influence of “slowly” distensible rs-compartments on pulmonary gas exchange is unknown and has yet to be studied.
Article PDF
Similar content being viewed by others
References
Ashbaugh DG, Petty TL, Levine BE (1967) Actute respiratory distress in adults. Lancet 2: 319–323
Murray JF, Matthay MA, Luce JM, Flick MR (1988) An expanded definition of the adult respiratory distress syndrome. Am Rev Respir Dis 138: 720–723
Gattinoni L, Pesenti A, Bombino M, Baglioni S, Rivolta M, Rossi F, Rossi G, Fumagalli R, Marcolin R, Mascheroni D, Torresin A (1988) Relationship between lung computed tomographic density, gas exchange and PEEP in acute respiratory failure. Anesthesiology 69:824–832
Wolf G, Eberhard L, Guttmann J, Bertschmann W, Zeravik J, Adolph M (1992) Polymorphous ventilation: a new ventilation concept for distributed time constants. In: Rügheimer E (ed) New aspects on respiratory failure. Springer, Berlin Heidelberg New York Tokyo, pp 235–252
Katz JA, Ozanne GM, Zinn SE, Fairley HB (1981) Time course and mechanisms of lung-volume increase with PEEP in acute pulmonary failure. Anesthesiology 54:9–16
Brunner JX, Wolf G (1988) Pulmonary function indices in critical care patients. Springer, Berin Heidelberg
Finucane KE, Egan BA, Dawsan SV (1972) Linearity and frequency response of penumotachographs. J Appl Physiol 32:121–126
Janney CD (1959) Super-syringe. Anesthesiology 20:709–711
Matamis D, Lemaire F, Harf A, Brun-Buisson C, Ansquer JC, Atlan G (1984) Total respiratory pressure-volume curves in the adult respiratory distress syndorme. Chest 86:58–66
Gatinoni L, Mascheroni D, Basilico E, Fotic G, Pesenti A, Avalli L (1987) Volume/pressure curve of total respiratory system in paralysed patients: artefacts and corelations. Intensive Care Med 13: 19–25
Gottfried SB, Rossi A, Higgs BD, Calverley PMA, Zocchi L, Bozic C, Milic-Emili J (1985) Noninvasive determination of respiratory system mechanics during mechanical ventilation for acute respiratory failure. Am Rev Respir Dis 131:414–420
Rossi A, Gottfried SB, Zocchi L, Higgs BD, Lennox S, Calverley PMA, Begin P, Grassino A, Milic-Emili J (1985) Measurement of static compliance of the total respiratory system in patients with acute respiratory failure during mechanical ventilation. Am Rev Respir Dis 131:672–677
Sydow M, Burchardi H, Zinserling J, Ische H, Crozier TA, Weyland W (1991) Improved determination of static compliance by automated single volume steps in ventilated patients. Intensive Care Med 17: 108–114
Bertschmann W, Guttmann, J, Zeravik J, Eberhard L, Adolph M, Wolff G (1990) Atemzugweise Bestimmung von Compliance und Resistance am Beatmeten. Intensivmedizin und Notfallmedizin 27:42–47
Otis AB, McKerrow CB, Bartlett RA, Mead J, McIlroy MB, Selverstone NJ, Radford EP (1956) Mechanical factors in distribution of pulmonary ventilation. J Appl Physiol 8:427–443
Eissa NT, Ranieri VM, Corbeil C, Chasse M, Robatto FM, Braidy J, Milic-Emili J (1991) Analysis of behavior of the respiratory system in ARDS patients: effects of flow, volume and time. J Appl Physiol 70:2719–2729
Benito S, Lemaire F, Mankikian B, Harf A (1985) Total respiratory compliance as a function of lung volume in patients with mechanical ventilation. Intensive Care Med 11:76–79
Auler JOC, Saldiva PHN, Martins MA, Carvalho CRR, Negri EM, Hoelz C, Zin WA (1990) Flow and volume dependence of respiratory system mechanics during constant flow ventilation in normal subjects and in adult respiratory distress syndrome. Crit Care Med 18: 1080–1086
Chelucci GL, Brunet F, Dall'Ava-Santucci J, Dhainaut JF, Paccaly D, Armaganidis A, Milic-Emili J, Lockhart A (1991) A single-compartment model cannot describe passive expiration in intubated, paralysed human. Eur Respir J 4:458–464
Dall'Ava-Santucci J, Armaganidis A, Brunet F, Dhainaut JF, Nouira S, Morisseau D, Lockhart A (1990) Mechanical effects of PEEP in patients with adult repiratory distress syndrome. J Appl Physiol 68:843–848
Marini JJ, CrookeIII PhS, Truwitt JD (1989) Determinants and limits of pressure-preset ventilation: a mathematical model of pressure control. J Appl Physiol 67:1081–1092
Author information
Authors and Affiliations
Additional information
The work was performed at the Klinik für Anaesthesiologie und Transfusionsmedizin der Universität Tübingen
Rights and permissions
About this article
Cite this article
Fretschner, R., Laubscher, T.P. & Brunner, J.X. New aspects of pulmonary mechanics: ‘slowly” distensible compartments of the respiratory system, identified by a PEEP step maneuver. Intensive Care Med 22, 1328–1334 (1996). https://doi.org/10.1007/BF01709546
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01709546